tanks

intro.md

  1---
  2title: Tanks Introduction
  3scripts:
  4  - assets/js/tanks.js
  5  - assets/js/figures.js
  6---
  7# Tanks Introduction 
  8
  9<figure>
 10  <canvas id="shortround"></canvas>
 11  <figcaption>"ChashTank" dominates this short round.</figcaption>
 12  <script type="text/javascript">
 13    start("shortround", shortround);
 14  </script>
 15</figure>
 16
 17Tanks is a game in which you pit your coding abilities against
 18other hackers.  You write a program for your tank, set it out on
 19the battlefield, and watch how it fares against other tanks while
 20running your program.
 21
 22Each tank has a turret-mounted laser, two treads, up to ten
 23sensors, and a diagnostic LED.  Sensors are used to detect when
 24other tanks are inside a given arc.  In the examples on this page,
 25"triggered" sensors turn black.  Most tanks will take some action
 26if a sensor is triggered, such as changing speed of the treads,
 27turning the turret, or firing.
 28
 29Tanks are programmed in Forf, a stack-based language similar to
 30PostScript.  Please read the [Forf manual](forf.md) to learn more
 31about forf, and the [Tanks procedure reference](procs.html) for a
 32description of Tanks extensions.
 33
 34## Quick Start for the Impatient
 35
 36<figure>
 37  <canvas id="default"></canvas>
 38  <figcaption>"Crashmaster" pwns the lame default tank provided in this section.</figcaption>
 39  <script type="text/javascript">
 40    start("default", default_);
 41  </script>
 42</figure>
 43
 44To get started, head over to the designer for your game,
 45and use the following example tank.  This tank will
 46move around, turn the turret, and fire if there's something in
 47front of it.
 48
 49    Sensor 0: 50 0 7  ☑
 50    Sensor 1: 30 0 90 ☐
 51    
 52    get-turret 12 + set-turret!         ( Rotate turret )
 53    37 40 set-speed!                    ( Go in circles )
 54    0 sensor? { fire! } if              ( Fire if turret sensor triggered )
 55    1 sensor? { -50 50 set-speed! } if  ( Turn if collision sensor triggered )
 56
 57This tank can be improved!
 58Watch other tanks in your game to get ideas about how to improve yours.
 59Don't forget the [Forf manual](forf.md) and the
 60[Tank procedure reference](procs.md).
 61
 62## Tank Specifications
 63
 64<figure>
 65  <canvas id="antlion"></canvas>
 66  <figcaption>"Ant Lion" nails "Rabbit With Gun".</figcaption>
 67  <script type="text/javascript">
 68    start("antlion", antlion);
 69  </script>
 70</figure>
 71
 72Your PF-255 autonomous tank is built to the exacting
 73specifications sent to our factory in New Khavistan.  All
 74distances are in meters, angles in degrees.
 75
 76
 77Tank size
 78: The targettable area of the tank—the part which can be hit by a cannon—is a circle about 7½ meters in radius.
 79
 80Speed
 81: Each tread can have a speed between -100 and 100.  This is in
 82  percentage of total speed for that tread, where total speed is
 83  roughly 7 meters per turn.
 84
 85Sensors
 86: Each sensor has a maximum range of 100 meters.  Of course, you
 87  don't have to use the full range.  Sensors may be attached to
 88  the turret (they turn along with the turret), or left fixed to
 89  the tank.
 90
 91Turret
 92: Turret angle can be set between -359° and 359°, with 0° directly
 93  in front of the tank.  Be aware that it takes time for the
 94  turret to swing around: the turret can swing about 45° per turn.
 95
 96Cannon range and recharging
 97: When the cannon is fired, it obliterates everything for 50
 98  meters in front of it.  It takes around 20 turns for your cannon
 99  to recharge after it's been fired, so only shoot when you feel
100  like you're going to hit something.
101
102Good luck blowing everybody up!